Popular Topics offer some links including: https://getpocket.com/explore/must-reads?src=ff_new_tab https://getpocket.com/explore/technology?src=ff_new_tab https://getpocket.cdn.mozilla.net/explore/trending?src=ff_new_tab (linking to CDN; it's another bug maybe?) The abbreviation of Firefox is fx, not ff [1]. Since this is part of an official product, the preferred abbreviation should be used instead, like src=fx_new_tab. [1] http://website-archive.mozilla.org/www.mozilla.org/firefox_releasenotes/en-US/firefox/releases/1.5.html#FAQ

Fixed by https://github.com/mozilla/activity-stream/pull/3500 to be uplifted via bug 1400353.